Such a packing unit is known from DE GM 84 03 230.
The outer envelope in the known unit is an outer box. The tray is placed therein in order to form a second layer of cartons on a first layer of cartons which are arranged separately in the outer box. The outer box is closed at its lower side and at its upper side by means of partly overlapping flaps which are fixed in closed position with adhesive tape. The outer box has in its side walls perforation lines and tear-off strips which merge into one another to facilitate the removal of its upper side and portions of its side walls and to render the cartons with lamps of the upper layer accessible.
It is a major disadvantage of the known unit that voluminous remainders of packaging material are created, which cannot be worked into flat remainders except with great difficultly, both during opening of the outer box and after all cartons have been removed therefrom. Another major disadvantage is the comparatively large quantity of material required for the outer box with its overlapping bottom and lid flaps. A further disadvantage is that the blank of the box must first be shaped into a sleeve through connection of a first side wall to a last side wall before the outer box can be finally shaped. The box can only be used for accommodating the cartons with lamps inside after it has been given its final shape by closing of the bottom. The cartons present on a tray in the outer box must also be put in the outer box one by one, because no space is available along the sides of the outer box in the case of a rattle-free packaging for holding a filled tray and putting it in the box in one operation.
Another disadvantage of the known unit is that the cartons of the lower layer can only be removed from the outer box one by one initially. This is inconvenient especially where remainders of the outer box at the point of sale or use are not acceptable, for example, because voluminous remainders of packaging material result therefrom in the end.
U.S. Pat. No. 1,888,855 (1932) discloses a packing unit in which six upright open sleeves each with an electric lamp are passed into a cardboard sleeve which is lying on one of its sides. Tags are stamped from the cardboard sleeve which project into the outermost sleeves with lamps and fix said sleeves. This unit is not suitable for displaying a comparatively large number of lamps conveniently and quickly for sale or use.